1. Field of Invention
The present invention relates to a projector which divides light from a light source into a plurality of partial light beams, which converts the plurality of partial light beams into one type of polarized light beam polarized in substantially the same direction by a polarization conversion element, which changes the polarized state of the polarized light beam by an electro-optical device, which selects a state by a polarization selection element to form an optical image according to image information, and which enlarges and projects the optical image.
2. Description of Related Art
Recently, attention has been focused on projectors using a reflective-type liquid crystal device. In such a reflective-type liquid crystal device, the pixel density can be increased by forming a structure, such as a transistor, for driving liquid crystal under a reflecting mirror. Therefore, the reflective-type liquid crystal device has the advantage of realizing a clear projected image with high resolution, compared with the case where a transmissive liquid crystal device is used.
In addition, in projectors using an electro-optical device, such as a liquid crystal device, in order to reduce the size of the entire device while realizing a bright projected image without display nonuniformity, the use of an integrator optical system or a polarization conversion element has been proposed (Japanese Unexamined Patent Application Publication No. 8-34127, and Japanese Unexamined Patent Application Publication No. 10-232430, etc.). In the integrator optical system, light from a light source is divided by a light beam dividing optical element into a plurality of partial light beams to form a plurality of light source images, the light source images are considered as dummy light sources, and light from the plurality of light source images is superposed on a liquid crystal panel, whereby illumination light having a uniform intensity distribution can be obtained. In the polarization conversion element, light from a light source is divided into a plurality of partial light beams to perform polarization conversion and then, the light is superimposed on a liquid crystal device, whereby illumination light polarized in the same direction is obtained.
For this reason, it is thought that a brighter projected image with high resolution and without display nonuniformity can be realized if the integrator optical system and the polarization conversion element are used in combination in the projector using the reflective-type liquid crystal device.